Surface receptacle



Oct. 11, 1955 E. P. MCKINLEY 2,720,636

SURFACE RECEPTACLE Filed Jan. 2e, 1955 United States Patent O SURFACERECEPTACLE Benjamin P. McKinley, Evanston, lli.

Application January 26, 1953, Serial No. 333,104

3 Claims. (Cl. 339-192) This invention relates to surface receptacles ofthe character adapted to be secured to a wall for receiving the plug ofa cord for an electric range, for example, in supplying current to thelatter.

Receptacles of the character under consideration usually are of thethree terminal type for use in conjunction with the three wire systemsgenerally employed in supplying current to electric ranges or other likecurrent using apparatus. The conductors for the relatively heavy currentsupplied to such receptacles generally are in the form of cablesconsisting of two relatively large rather stif conductors of severalwires each and a third conductor consisting of wires of smaller gaugeand of considerably greater flexibility. In making installations of suchreceptacles it is desirable that the terminals to which the conductorsare to be attached be such that the attachment can be effectedexpeditiously by an electrician without having to sharply ex or bend thestiff cables in attaching them to the terminals and also without thenecessity of handling separable parts of cable attaching means which maybe dropped and lost or otherwise occasion loss of time of theelectrician. In addition to providing a novel construction andarrangement of parts which facilitate installation and hook-up of thereceptacle, it is an object of the invention also to provide aconstruction all the parts of which can be assembled readily into anoperative unit for packaging at the factory without loose parts whichmust be individually handled and assembled by the workman at the time ofinstallation of the receptacle.

Another more specific object of the invention is to provide a receptacleof the character mentioned which is provided, preferably, with threeterminals for a three conductor supply circuit to which terminals theconductors can be attached without substantial lexing and bending intoposition for attachment, and at least two of which terminals haveslidable clamping members for securing the relatively stiif conductorsto the terminals.

Other objects of the invention relate to various features ofconstruction and arrangement of parts which will be apparent from aconsideration of the following speciiication and accompanying drawingwherein:

Figure l is a front elevational View of an assembled receptacle of aconstruction which is illustrative of the present improvements;

Fig. 2 is a side elevational View of the receptacle shown inFig. l;

Fig. 3 is an elevational view of the receptacle with the cover plateremoved;

Fig. 4 is a bottom view of a detached molded three cell insulatinghousing for the receptacle contact members which are shown in positionin the cells and illustrating also the conductor clamping means eachforming a part of one of the contact members;

Fig. 5 is an enlarged longitudinal sectional view taken along lines 5-5of Fig. l;

Fig. 6 is a broken sectional view taken on line 6 6 of Fig. 5;

ice

Fig. 7 is a plan View of the central terminal member shown in Fig. 6;

Fig. 8 is a sectional View of the terminal member taken on line 8 3 ofFig. 7; and

Fig. 9 is a sectional View taken on line 9-9 of Fig. 7.

in Fig. l of the drawing a front elevational view of the improvedreceptacle is shown in assembled relation, which in use is adapted to besecured to a wall at a convenient location with respect to the currentusing device which it is to serve, generally an electrical range of thetype used domestically. rlhe receptacle shown comprises a metal base 10(see Fig. 5) integral with an end 11 which constitutes the lower end ofthe assembly when installed for use. Secured to the other or upper endof the base is an insulating receptacle or housing indicated generallyby the numeral 12 which is attached to the base 10 after assemblytherein at the factory of the spring contacts later described. Thehousing is attached to the base 10 by a single screw 13 as shown in Fig.5. Preferably a nib or small projection 14 is provided on the perimeterof the end of the housing 12 which fits within a small cut out or recess15 provided in the base for resisting angular displacement of thereceptacle with respect to the base after securement of the partstogether by means of the screw 13.

The housing 12 has three cells 16, 17 and 18 for receiving electricalcontact members 19, 29 and 21 prior to attachment of the housing to thebase itl. A fourth cavity 22 is shown but it is nonfunctional and ismerely provided for reducing the quantity of plastic required in moldingthe housing 12. The three cells 16, 17 and 1S, as stated, are adapted tohold the contacts 19, and 21, but the contacts are provided withterminal members which extend from the cells at the inner or lower endsthereof as shown in Fig. 6. The contacts per se are identical and areadapted to make electrical contact with the blades of a three blade plug(not shown) when the blades are pressed through restricted openings orslots 16a, 17a and 18a at the outer ends of the cells. While the Contactmembers 19, 29 and 21 are similar, each has a terminal bar or extensionpeculiar to its location in the unit. The terminals designated 19a, 26aand 21a of the respective contacts are of bar form, the terminal 19abeing straight while terminals 20a and 21a are longer, as shown in Fig.6, and are shaped angularly as indicated also in said iigure to groupthe terminal ends in substantial parallelism with the terminal 19a. Thefree ends of the terminals mentioned are turned inwardly, as indicatedat 23, to space the terminals from an electrical insulating member 24disposed between the contacts and terminals and the plate 10.

The terminal members 19a, 20a and 21a are secured to the respectivecontacts 19, 20 and 21 by any approved means, that shown in Fig. 8 beingillustrative and consisting in partially punching from the end of theterminal strip the rivet-like extrusions 25 which are passed throughopenings in the contact and riveted over. Another attaching means may beused to provide good electrical Contact between the terminal strips andthe contact members which are of copper, usually. The heads of therivet-like extrusions 25 cooperate with the inturned ends 23 in spacingthe intermediate portions of the bar terminals from the insulator 24.

Mounted on each of the terminal members 19a, 2tlg and 21a are cablereceiving and clamping rings 26. The rings are rectangular in sideelevation as shown in Fig. 9 and each is provided with a threadedpassage at the upper side as viewed in Fig. 6, which carries a cable orconductor clamping screw 27. The ring 26 of the intermediate terminalstrip 19a is closely disposed between the downwardly turned end 23 andthe adjacent wall of the housing 12 and so is not slidable along thestrip as are the rings 26 of the terminal strips a and 21a when theclamping screws are loosened. These sliding clamping rings are ofsubstantial convenience in connecting the conductors of `aV cable 28 tothe terminals in the receptacle. With the cover of the receptacleremoved and the base plates secured to a wall by screws passed throughsuitable openings, such as openings 29 indicated in Fig. 6, and with theinsulating housing and contacts in assembled relation upon Vthe base asthe same comes from the factory, the cable is passed through a knock-outopening in the end 11 as shown or in the base 10 and clamped to the baseby means of the usual outlet box clamps 30. The cable 28 shown is of thethree conductor type, the intermediate conductor 31 being the return orground conductor. Such Y a conductor, as shown, is usually formed ofWires of rela.-

tively small gauge and is quite flexible, and a workman l Vhas nodifiiculty flexing it and inserting the bared end into the ring 26. ofthe terminal 19a. Tightening therespective screw 27 completesVtherconnection of the conductor 31; The-conductors V32 and 33 areformed of a number of wires of relatively heavy gauge Vand are quitestiff. FleXing the'conductorsand inserting theminto openings, channels,or'rpassages designedV to receive 4them heretofore has sometimesconstituted an annoying chore.

With the present improvements the rings 26 of the termi-l nals 20a,Zlaare merely pushed back or upwardly along the terminals in a directionaway from the `free ends thereof and the workman then lays the strippedand bare, end of the conductor successively upon the respectiveterminals after which he slides the respective rings over the baredwires and tightens the screws 27 to complete the electrical connections.The cover plate 34 is then placed in position on the receptacle. l Y

The cover plate 34, of metal or plastic, comprises a front wall 35 andside walls 36. YThe forward edge of the 1 Vfront Wall rests uponshoulders 37 provided in the plastic `housing 12 .and at the oppositeend has an inwardly turned portion 38 which overlies the inwardlydisposed outer edge 11a of the rear wall 11. The wall 11 has a tab 39provided with a threaded opening for receiving a' screw 40 passedthrough an opening in thel coverV for holding the latter in position asshown in Fig. 5. Y

It will be noticed that the rings 26 of the several terminals areconfined Vthereon bythe downwardly turned ends 23 of the terminal barsand hence, even when the screws 27 are loosened the rings cannot drop oithe bars. The

' along said base plate and a ring loosely surrounding each screws 27preferably are staked againstrcomplete Withdrawal from the rings andhence when a Workman removes the cover plate 34, he has an `integratedstructure t to attach to the wall and towhich the electrical conductorsY are latter attached. The provision of the slidable rings 26 on theterminalbars 20a and 21a simpliiies the work involved in attaching therelatively stii conductors 32 and 33 as described.

While I have shown and described a surface receptacle which isillustrative of my improvements, variouschanges t in details may beresorted to withoutV departure from the terminal barfand provided with aconductor clamping screw for clamping a bared end of a conductor withinthe ring into electrical contact with the respective bar, two of saidbars projecting from said housing a distance adequate to enable therings thereon to be slid along the bar over the ends ofa conductor onthe bar 'preparatory to clamping the conductor'to the bar. Y

2. A n electrical vreceptacle .comprising a base plate adapted to beattached to a wall, an insulating housing secured to said plate andprovided with vcells for electrical contact members, said cells beingopen at the bottom ends and provided with passages at the outer ends foraccommodating the blades of an loutlet plug inserted therethrough forelectrical connection with contact members Within the cells, contactmembers Within the cells provided with bar terminals extendinglongitudinally of the plate, from one side of said housing and eachhaving a free end Y turned ltoward y'said plate, Yan lelectricalinsulatingrnember disposed between the plate and said vcontactmembersVand the bar terminals thereof .and engaged bythe inturned ends of saidbar terminals forrspa'cing thelatter from said insulating member, andconductor .receiving-each looselysurrounding one of said -bar terminalsand conined thereon by said housing and the inwardly `turned end of thevrespectiveV bar and. each provided 4with a clampV Y screw at least twoof said Abars being of Ysuflicient length toV accommodate, slidingmovement of the respective rings therealong to enable therings to beslid'upwardly of thel bars `and thus yenable ythetbared ends ofconductors to` be placed upon the lower portionsof the bars andthereafterV Y slid downwardly `over said bared ends for attaching saidends to the bars by the respective screws.

, 3. An electrical receptacle comprising a baseY plate adapted to beattached to a wall,Y an insulating housing secured to the plate at oneend thereof and provided with Y cells for electrical contact members,said cells being-open Y at -the ybottom Vends and provided with passagesat the outer ends for 4accomrnodatingvthe blades of an Voutlet pluginserted therethrough 4for electrical connection with contact memberswithin the cells, Contact members within said cells provided with Vbarterminals V.extending Vfromrzsaid,

housing longitudinally .of the tbaserand each-provided with afreeenddirected inwardly toward-said plate, an insulating member on the-basebeneath saidrcontact members and bar terminals, and rings on said barterminals between theV inturned ends thereofV and said housing and :eachprovided with a clamping screw for clamping tothe bar terminal a baredend .of a Aconductor extending within the Y ring, atleast two ofl saidbar terminals beingyof suicient length to enable said rings `to be slidawayfromsaid free end portions a distancegto enable the bared ends of4condoctors to be placed onlsaid free end portions and thereafter movedto encompassing relation over said rconductor ends prior totighteningfvthe screws for clamping the conductor ends into iirm.electrical contact with saidV `bar terminals.

References Cited in the file of this patentV UNITED STATES PATENTSY1,967,901 Y Kempton July 17, '1934v 2,145,556 Rypinski June 31, 19392,193,202 Millermaster Mar. V12, -1940 2,203,337 Mebold June -4, V194032,287,762 Rogoff` Iune 23, 1942 2,602,104 Hubbell et al. 'luly l, 1952

